1. Field of the Invention
The present invention relates to electro-static discharge (ESD) protection devices.
2. Description of the Related Art
An example of a conventional ESD protection device is disclosed in International Publication No. WO2011/096335. The ESD protection device includes a base body, a first discharge electrode and a second discharge electrode that are provided in the base body and face each other in a lamination direction, and a discharge auxiliary electrode that is provided between the first discharge electrode and the second discharge electrode and electrically couples the first discharge electrode and the second discharge electrode.
The present inventor has discovered that the conventional ESD protection device is problematic in its low resistance to continuous application of ESD by actually using the conventional ESD protection device. The present inventor has reviewed this phenomenon diligently and determined the causes described below.
When ESD is applied, only internal discharge occurs in a discharge auxiliary electrode and energy is concentrated. Thus, thermal shock is concentrated in the discharge auxiliary electrode and the discharge auxiliary electrode deteriorates, and dielectric strength at the time of continuous application of ESD decreases.